The objective of this research is to develop an erbium:YAG laser system capable of drilling dental hard tissues whilst minimizing the need for dental anesthesia. Many Americans today evade timely dental care out of fear of the mechanical drills and the dental anesthetic needles. A non-mechanical, non-contacting laser drill, without the grinding, whirring noise would be a boon to these patients. However, until recently, laser drilling of intact tooth tissue, using the carbon dioxide laser and the Nd: YAG laser had only resulted in charring and cracking of enamel. In sharp contrast, the 2.94 micron Erbium: YAG laser has been shown to drill fine, sharp holes in enamel and dentin, with no ultrastructural damage and no thermal elevations exceeding the physiologic limits of dental pulp. And, as the duration of the erbium laser pulses used is in the microsecond range, well below the pain threshold of the brain, laser drilling of teeth may be almost painless. In Phase I, in vitro tooth exposures of pulsed Er: YAG lasers at varying power levels, exposure times and spot sizes will be made to determine the resultant temperature changes and depths of cuts. SEM examination, X-ray diffraction analysis and FTIR spectroscopy will be done of the lased area. Tooth drilling of fiber transmitted erbium laser will be studied. These findings will be applied in Phase II research on an animal model and for applying FDA approval.